Converting a Join Query into a Sub Query

I'm attempting to write a sub query that wold accomplish the same results as the join query shown below.

SELECT Department_to_major.DNAME
FROM Department_to_major
INNER JOIN Course
ON Department_to_major.Dcode = Course.OFFERING_DEPT
WHERE Course.COURSE_NAME LIKE '%INTRO%'
GROUP BY Department_to_major.DNAME